Medical devices for treating narrowed and occluded blood vessels are well known in the art. When treating a narrowed or occluded blood vessel, it is often necessary to provide support to the vessel while simultaneously allowing for the perfusion of blood. Collapsible and expandable stents and stent delivery systems have been used for this purpose. A stent delivery system typically inserts a stent into the lumen of an anatomical vessel to keep a previously blocked passageway open while simultaneously allowing blood to perfuse through the stent. An example of such a system is disclosed in the U.S. Pat. No. 6,966,923 (the '923 patent) to Gittings.
The '923 patent discloses a collapsible and expandable support. The support is collapsed and disposed within a sheath, being axially moveable within the sheath. The sheath is inserted into the lumen of a blood vessel, and an external force applied to the support axially moves the support outwardly of the sheath into the lumen of the blood vessel causing the support to expand. The support expands outwardly against the interior walls of the blood vessel, unblocking and supporting the blood vessel while allowing for the perfusion of fluid. The collapsible and expandable support disclosed in the '923 patent remains in the lumen of the blood vessel, supporting the passageway, while the sheath is removed.
Additional collapsible and expandable stents are disclosed in the prior art which include a guidewire attached to the collapsible and expandable support. An example of such a system is disclosed in the U.S. Pat. No. 5,034,001 to Garrison et al. (the '001 patent). The '001 patent discloses a sheath and a guidewire being axially moveable within the sheath. An expandable and collapsible support is disposed on the guidewire with the support being axially moveable inwardly of the sheath to collapse the support and is axially moveable outwardly of the sheath to expand the support. The '001 device does not use an expandable cage to block tributary vessels.
In addition to stents being collapsible within a sheath, the prior art also discloses stents being collapsible without a sheath. The U.S. Pat. No. 4,921,484 to Hillstead discloses a support end disposed on a guidewire. A mechanism for moving the proximal support end axially along the guidewire opposite the distal support end collapses the support. The guidewire and support are inserted into the lumen of a blood vessel and a mechanism for moving the proximal support end axially along the guidewire towards the distal support end causes the support to expand outwardly against the blood vessel, supporting the blood vessel while simultaneously allowing for the perfusion of fluid through the vessel. The Hillstead device does not use an expandable cage to block tributary vessels.
While the prior art stents support a blood vessel allowing for the perfusion of blood, it is oftentimes necessary to isolate a blood vessel during surgical repair. In such circumstances, the side branches or sections of major vessels are typically clamped to prevent retrograde or antegrade flow to or from smaller vessels that branch off of major vessels. By occluding these vessels, a clearer operating field is achieved and less blood units may be required during the procedure.